The use of enzymes, for example proteases and lipases, offers considerable advantages in cleaning applications. For example, WO 97/02753 A1 discloses that enzymes can be used to remove protein- and lipid-containing soils at low temperatures and without the need for additional chemicals. Thereby, the use of enzymes in cleaning applications increases the material compatibility, decreases the energy costs, reduces water consumption, and reduces the health and environmental risks that would result from the use of chemicals.
Enzyme-based cleaning products are used for example in the food industry, in particular for the cleaning-in-place of equipment used to process food or beverages. Here, cleaning-in-place refers to the cleaning of process equipment by circulating a cleaning solution through the equipment without the need to disassemble the equipment prior to the cleaning procedure. A particular example for the use of enzymes in cleaning applications is the use of proteolytic enzymes for the cleaning of membranes in used to process dairy products.
Enzymes can also be employed for the cleaning of textiles or other laundry articles at low temperatures.
A problem associated with the use of enzymes in the cleaning-in-place of food processing equipment is that they might contaminate and potentially degrade the foodstuff, if they are not completely inactivated after the cleaning step. For example, a lipase might degrade any dairy products coming into contact with the enzyme. This might change the taste of the foodstuff and potentially prevent its commercial use. Therefore, an effective and cost-efficient way to inactivate the enzymes is needed.
Similarly, residual enzymes in laundry-cleaning applications might degrade laundry components, especially if the laundry material is a textile of biological origin, e.g. wool, resulting in degradation products that have an unpleasant odour.
Proteases are commonly inactivated by very high or very low pH. Lipases, on the other hand, are less sensitive towards pH and require the combination of a pH lower than 2 and a temperature in the range of 40° C. to 70° C. for their inactivation. However, this method of inactivation is potentially damaging to the equipment that is to be cleaned. For example, an acid treatment might have a corrosive effect on the surfaces of process equipment and on filtration membranes used therein. Also, the rather high temperature required entails an increase in energy costs. Furthermore, the use of large volumes of acidic inactivation compositions requires their neutralization and proper disposal of the liquid waste.
Therefore, the technical object of the present invention is to provide a method of enzyme inactivation that affects a broad range of enzymes, that is effective at ambient temperature (i.e. 20° C. to 30° C.), that does not require strongly acidic or basic conditions, and that has a high material compatibility in order to be used in cleaning-in-place applications.